Detachable fastening for drill bits



March 22, 1938. M, K TRELL 2,111,785

DETACHABLE FASTENING FOR DRILL BITS w Filed Jan. 6, 1956 2 Sheets-Shee;l

IN V EN TOR.

By M%%% r, I ATTORNEYS.

Patented Mar. 22, 1938 2,111,785 DETACHABLE FASTENING FOR DRILL BITSMilton J. Kittrell, Qttumwa, lowa, assignor to Hardsocg ManufacturingCompany, Ottumwa, Iowa Application January 6, 1936, Serial No. 57,651

8 Claims.

My invention relates to drills, drill heads and drill bits and tomethods and. means of fastening the bits into their operating positions;an object being in my invention to provide a new and very eflicientdetachable fastening for drill bits in the head of mining drills and thelike.

A further purpose of my invention is to provide a method and means ofdetachably securing drill bits into their supporting sockets with butone bit in each socket and with it a spring binding member to hold thebit in place instead of the usual wedge that is so commonly used forsuch purposes.

A further purpose of my invention is to provide in a drill head and inthe socket thereof with a drill bit a spring engagement or a springbinding member for thedrill bit instead of the usual tapering wedgeholding member; whereby the spring binding member, when normallystraight, may hold the drill bit in a curved socket and will utilize theprinciple involved where a spring inserted in the socket alongside ofthe adjacent surface of the drill bit will cause such a spring thuscurved in the socket to have a tendency to straighten out, resulting insuch a spring thus exerting a lateral pressure against the adjacentflanking sur-- face of the drill bit. On the other hand where a bindingspring within the scope of my invention, which may be normally curved ifinserted in a straight socket with the shank of a bit will thus haveatendency to assume its normally curved shape resulting in an exertedpressure against the adjacent flanking surface of the drill bit, tendingto hold the bit substantially in place in the socket. A further purposeof this invention is to provide means for holding a drill bit in thedrill head socket and I utilize a flanking spring pressure in the socketwherein the shape of the socket forces the spring inserted with thedrill bit to assume some shape that it does not normally have so thatthe tendency for the spring binding member to resume its normal shapemay exert a lateral flanking pressure against the adjacent surface ofthe drill bit regardless of the original normal shape of the bindingspring whether it be normally a straight spring to be bent in a curvedsocket, a curved spring to be straightened in a straight socket a. wavyspring which is somewhat straightened in a curved orst-raight socket ora U-shaped spring which would flank two opposite sides of a bit withinthe socket.

A further purpose of my invention is to provide a binding spring membershaped to permit it to engage the socket wall either on the inside oroutside surface with the binding member, for instance, hooking into therecess of the wall surface or hooking over a holding knob thereof sothat the spring may hold itself in place in the socket when the drillbit is knocked out.

I attain the purposes of my invention by the method and means describedin this specification, recited in the claims and illustrated in thedrawings wherein the same reference numerals indicate like parts in thedifferent figures.

Referring to the figures:

Fig. 1 is a side View of a drill and drill head with my drill bitfastening.

Fig. 2 is a side view of one of the drill heads containing my drill bitsecured therein.

Fig. 3 is an end View of the drill head and drill shown in Fig. 1.

Fig. 4 is aside view of one of the drill bits shown when laid on thebinding spring before the two are forced into the socket together.

Fig. 5 is a sectional view of a portion of one of the drill heads,illustrating the manner of fitting 9 the curved bit into the curvedsocket where it is held by the binding spring.

Fig. 6 is a perspective of one of the drill bits, defining a part of myinvention.

Fig. 7 is a perspective of one of the binding springs mounted in. thedrill head with the drill bit for holding the bit in place.

Fig. 8 is a horizontal section through a portion of the drill headillustrating one manner of holding the binding spring in place, while adrill bit is removed from the sccket.

Fig-9 is a perspective of one of the forms of binding spring used on thetype of socket shown in Figure 8 and in Figure 27 and where such aspring may be normally bent. it would be used in the manner illustratedin Figure 24 where it is adapted to hold a straight bit.

Figure 10 is a perspective of a normally straight binding spring forusein a curved socket and provides with a divided shoulder. where it maybe used in a situation shown in Figure 12 where the rear of the sockethas upright side shoulders for the spring to abut against. It isconceivable that the curved spring shown in Figure 23 could be used in astraight socket with its terminal shoulder divided where the straightsocket would have its rear end form of upright side shoulders asillustrated in Figure 12 in section.

Figure 11 is asection of a straight socket wherein a curved bindingspring as. shown in Figures 23 F and 24 is used with an angularly formeddrill bit.

Figure 12 is a sectional view of a curved bit in a curved socket havingupright side shoulders in the rear of the socket and using a bindingspring such as is illustrated in Figure 10.

Figure 13 is a sectional view showing a wavy binding spring such as isillustrated. in Figure 22 in use in a curved socket. The same kind of aspring could be used if desired in a straight socket.

Figure 14 is a sectional view showing how a normally straight bindingspring as illustrated in Figure '7 may be used with a curved bit and.curved socket with the rear stop shoulder of the socket above ratherthan below the center as shown in Figure 13.

Figure 15 is a sectional View showing how a binding spring in the formillustrated in Figure 25 may be used with a relatively short bit to fillup space in the rear of the socket. It is conceivable that any one ofseveral types of stop shoulders could be used at the rear of the socketbut in this instance there is illustrated an upright side shoulder suchas is illustrated in Figure 12 for the binding spring to abut against.

Fig. 16 is a relatively horizontal section illustrating the manner inwhich a U-binding spring normally curved as illustrated in Figure 18could be used to flank the sides of the bits. This illustration showsupright side shoulders at the rear of the socket for the binding springsto abut against.

Fig. 17 illustrates in section the use of a normally straight U-springin a curved socket, (see spring in Figure 19). In this illustration theU-spring fits under the bottom and over the top and around the rear endof the curved bit while the socket has its stop shoulders across the topand bottom for the spring to abut against.

Fig. 18 is a perspective of the type of spring adapted to be used in asituation illustrated in Figure 16.

Fig. 19 is a perspective of one of the normally U-straight springs shownin use in Figure 1'7.

Fig. 20 is a sectional view showing one of the binding springs asillustrated in Figure '7 but used in a manner wherein the springs reston top of the bit with the rear shoulder of the spring abutting the rearstop shoulder of the socket disposed across the bottom of the socket.This socket stop shoulder, however, would work just as well across thetop.

Fig. 21 is a perspective of a notched or grooved or corrugated springnormally straight as shown in Figure 7 and roughened on the top side tomore firmly hold against one of the bits which may be likewise roughenedalong the surface adapted to contact the spring. This spring could benormally curved as shown in Figure 23 for use on a straight bit or anangularly formed bit as shown in Figure 11.

Fig. 22 is a waved binding spring as shown applied in Figure 13. Thisspring could likewise have a generally curved shape as shown in Figure23 for use with a straight bit as pointed out in the description ofFigure 21.

Fig. 23 is a perspective of a normally curved binding spring adapted tobe used with a straight bit and straight socket or with a bit made in anangle as shown in Figure 11.

Fig. 24 illustrates in perspective the manner of setting a straight biton the binding spring illustrated in Figure 23.

Fig. 25 is a perspective of one of the binding springs shown in use inFigure 15 for filling the space in the socket when a shorter tooth isused.

Fig. 26 is a perspective of that form of binding spring shown in Figure25 with the rear end merely doubled over where a smaller space needs tobe taken up.

Fig. 2'7 is a sectional view illustrating one of the binding springsshown in Figure 9 as used where the holding end of this spring engages anotch in the top surface of the casting over the socket in the drillhead.

In the detailed disclosure of my invention and the preferred method ofusing the same, the salient features thereof will be set forth as itwill be shown wherein my invention surpasses the merits of some otherknown inventions for such purposes.

As is evidenced by some of the drill bit fastenings now in use, it hasbeen the common practice to secure the drill bits in place in the drillhead by a wedge of one form or other and the vibration attending adrilling operation usually has a loosening effect upon such wedges,causing annoyances and loss of time.

In my present invention, I obviate this trouble by securing the drillbit into its socket in the drill head by using a metallic binding springadapted to tightly fit into the drill bit socket flanking the adjacentsurface of a drill bit, so that this binding spring member may, whenforced into the socket with the bit, take a position conforming to thesocket curve, thus assuming a position which makes the spring exert alateral or flanking pressure against the adjacent surface of the drillbit in the socket holding the bit firmly into its operative position inthe socket of the drill head. This flanking pressure will thus beexerted against the drill bit and socket wall because of the tendency ofthe inserted spring member to spring back to its normal position. Thusin a curved socket would be used a normally straight or wavy springwhile in a straight socket would be used a normally curved or wavyspring.

In the meantime, there may be working conditions wherein it would bebest to leave the binding spring in the socket while the drill bit isbeing removed and I provide for this contingency in this invention.

I shall now disclose the method and means used in providing my newdetachable fastening for drill bits as the novel merits thereof arepointed out and while a mining drill will be discussed in this instance,it is not meant to limit the invention to mining drills, alone.

For instance, I shall first explain that form of my invention wherein Iutilize a normally straight binding spring, a curved socket with a drillbit after which I shall describe other forms of my invention and thepreferred manner of using the same.

A drill head I has a group of carefully spaced curved sockets 2 each forthe operative support of a drill bit 3 shaped with an approximatelysquare cross sectional area and bent to conform to the curve of thesesockets in the drill head.

Sockets 2 have a rear stop shoulder 4 to limit the extent to which bits3 can be forced back into them.

As a novel feature of my device, I provide a binding spring member 5preferably made of steel and having a terminal rear stop shoulder 6.This binding spring member 5 is normally straight and when bent it tendsto fly back to a straight position again; and when the curved bits 3 arefitted along the side of binding spring members 5, the sum of theircross sectional areas is equal to the transverse area of one of the bitholding sockets 2 and will thus fit these sockets when fitted therein.

Thus, when fitting a curved drill bit 3 into holding a straight socket.

that a knob 9 or a recess l3 could beengaged flin /785 one of the curvedsockets 2, the operator will place one of the bits 3 on binding springmember 5 as shown in Fig. 4. When the curved bit and normally straightspring are thus set together they are forced side by side back intosocket 2 which has the same curvature as bit 3, where they come to rest,as binding spring member 5 comes'against the rear end shoulder 6 ofspring member 5 touches the same.

Thus, when curved drill bit 3 is inserted into curved socket 2, withnormally straight binding spring 5, as when both are tightly flankedtogether they fill the socket, then the result is to bend the bindingspring member as it conforms to the curved shape of the socket wall.

This bending of binding spring 5, when it has a normal tendency to holda straight'position, has the effect of its exerting a lateral flankingpressure against the top or bottom side of bit 3' and thus acting as avery effective binding spring or securing means to hold the drill bits 3into their operating position in sockets 2 of drill heads I. r I

The effect will be the same whether the binding spring 5 is used aboveor below drill bits 3;

The major application of this invention will perhaps utilize the bindingspring with the simplest type of shouldert as shown in Fig. '7, butthere will be situations wherein the sockets 2 or one end of the bindingspring 5 may be modified so that this binding member may resist'removalas bits 3 are remove'dfrom socket 2.

For instance, the binding spring member '5 shown in perspective in Fig.9 is normally straight with a hooked forward terminal adapted to hookover a knob 9 in the drill head casting Hl'where the knob is normallyabove drill bit it It is obvious that spring binding member 7 could-benormally curved so that it 'Wlll exert a flanking pressure against theadjacent surface of the straight drill bit ll (see Fig. 24) or anangular drill bit l2 (see Fig. 27). Spring member 7, if curved normally,could obviously be used for It is also obvious by aretaining hookportion it for" holding the U-shaped binding spring member l5 within thescope of my invention if desired. v

In all of the figures running from Figure 8 to Figure 27, inclusive, Ihave illustrated'difierentforms and fitting arrangements of my inventionwith the thought that various operating conditions may prompt thesemodifications, all of which: it is, obvious, are within the scope of myinvention.

For instance, in almost any situation the rear end of the socket shouldbe left open to provide access either to the rear end of the drill bitor the rear end'of the binding spring member to permit the operator todrive the bit out of the socket.

In Fig. 10, I have illustrated a. normally straight binding springmember l5 provided with a rear terminal shoulder I1, having twouprightlydisposed side shoulders with a space between them providingtool access to the rear end l8 of drill bit 3 (see Fig. 12). In thisfigure the rear stop shoulders 19 in the socket are uprightly disposedfor the divided shoulders l! of spring binding member 15 to abutagainst. The same kind of shoulders 20 are illustrated in Fig. 15 forthe rear end of sockets 2 in holding the loop end 2| of a spring bindingmember 22 adapted to be used for filling space when the drill bit 3 getsshorter as shown in Fig. 15.

in some drill heads such as the one shown insection Fig. 11, the head 23may have in it a straight socket 24 wherein an angle bit I2 or astraight bit H may be used and with it a curved binding member 25 (seeFigs. 23 and 24), or a wavy binding member 26 may be used as isil1ustrated in Fig. 13 where wavy binding member 26 is shown in use witha curved drill bit 3. In this connection, it is obvious that wavybinding member 26 could be wavy and yet curved like binding member 25for use with a straight bit II or an angle bit l2.

The rear stop shoulder 4 in the curved sockets 2 or straight sockets 24may be at the bottom as shown in Figure 5, 11, 13 or 20 or this shouldermay be at the top as shown in Figs. 14 and 27.

Within the scope of my invention, I may choose to use a U-spring 21 (seeFigs. 16 and 18), which is normally curved for fitting into straightsockets as shown in Fig. 16; while spring 21', if desired, may be sprungas shown in Fig. 18 and also curved to fit along-side of curved bits 3in a curved socket 2.

Where the spring member may be desired above and below bits 3 and acrossthe rear end l8 thereof. With this arrangement shoulders 28 in socket 2(see Fig. 1'7), would be the stop means for spring l5 to abut against.

Spring I5, as will be noted, in Figure 19, may be curved as shown in thedotted lines in this figure to permit the hooked end thereof to be usedin the manner illustrated either in Figure 8 or Figure 27.

The binding spring member 5 may be set into socket 2 so that it will beflanking the top surface of curved bits 3 as shown in Figure 20.

Binding spring member 29 is the same as spring member 5 with theexception that its top surface 30 is roughened or corrugated to make itadhere more substantially to the drill bit surface.

Wavy spring 25 may be made generally straight in outline or it may bemade in a general curve as shown in Figure 23 but the generally straightspring would be used in a curved socket as shown in Figure 13, while acurved spring'would be used in a straight socket as shown in Figure 11.

Spring 3| is used for the same purpose as spring 22 and in'like manner,but this spring is adapted, by using the shorter loop 32, to use lessspace in a drill head socket.

It will thus be observed that my invention is adapted to be used in anumber of ways in several forms within the scope of my invention, all ofwhich forms fall within the scope of the generic idea of holding thedrill bit Within its supporting socket substantially by a spring bindingmember which exerts its holding pressure against the adjacent flankingsurface or surfaces of the drill bit because of the tendency of such aspring member to resume its normal shape after it is inserted into thesocket, the shape of which may bend the spring out of its normal shape.

Having thus described the nature of my invention, what I claim is:

1. A detachable drill bit, retaining spring and drill head combinationcomprising a metallic drill head provided with a plurality ofnoncircular drill sockets, metallic drill bits shaped to be received bysaid socket and a. retaining spring for each socket with a tudinallyunlike the sockets; whereby when a bit and a retaining spring areforcefully entered into one of said sockets, the spring member willexert a springy, flanking pressure against the adjacent bit side andsocket wall and tend to hold normal shape longi- F itself into operativeposition by the spring tendency to resume normal shape.

2. A drill head, retaining spring and drill bit combination comprising ametallic drill head pro vided with a plurality of curved bit sockets, anormally waved binding spring having an integral shouldered terminal anda curved drill bit adapted to operatively fit into one of said socketsin flanking position with one of said springs; said spring membernormally shaped longitudinally unlike the longitudinal shape of thesockets and when forcefully inserted into the socket with said bit willexert a flanking pressure against the adjacent side of the bit andsocket tending to hold the bit in place through its springy urge toresume normal position.

3. In a drill, the combination comprising a drill head, provided with aplurality of drill bit sockets, each having a non-circular crosssection, a drill bit and retaining spring for each socket and adapted tofill the socket when both are fitted therein together, said drill bithaving the longitudinal shape of said socket and said retaining springshaped to define a shouldered inner terminal for limiting the depth ofinsertion of said bit and normally curved along its length; whereby whensaid retaining spring is forcefully inserted in said socket with saidbit as it flanks the side thereof, this spring will exert a flankingpressure against said bit effectively retaining the same within thesocket as said spring thus tends to resume its normally curved position.

4. The combination in a drill of a drill head having a plurality ofstraight sockets, a drill bit for each socket and a U shaped metallicspring adapted to extend around the inner end of one of said bits whenthe bit is fitting into operative position in the socket and adapted toflank two opposite sides of said bits; said spring normally having aform unlike the longitudinal shape of said sockets; whereby when saidspring and bit are forcefully inserted together into said socketsrespectively, the tendency of said spring to resume its normal shapewill cause the same to exert a flanking pressure against the contactingsides of said bits, thus holding the bit in place in the socket.

5. The combination in a drill of a drill head having a plurality ofcurved sockets, a drill bit for each socket and a U shaped metallicspring adapted to extend around the inner end of one of said bits whenthe bit is fitting into operative position in the socket and adapted toflank two opposite sides of said bits; said spring normally having aform unlike the longitudinal shape of said sockets; whereby When saidspring and bit are forcefully inserted together into said socketsrespectively, the tendency of said spring to resume its normal shape,Will cause the same to exert a flanking pressure against the contactingsides of said bits, thus holding the bit in place in the socket.

6. A drill head, drill bit and retaining spring combination comprising adrill head having a plurality of curved bit sockets, a like number ofdrill bits shaped each to conform to said sockets longitudinally and alike number of retaining springs, each for one of said sockets andshaped to define a form other than the shape of said sockets, one end ofeach of said springs shaped to define a hook member, said drill headadjacent each of said socket openings provided with an integral lug tobe engaged by said hook of the spring, when the spring and bit aretogether forcefully inserted into each socket; whereby when thusforcefully inserted into said socket in flanking position to each other,then the springs tendency to resume its normal shape will force aflanking pressure against the adjacent surface of said bit, holding thesame in place and whereby when thus in operative position said hookedterminal of the spring will engage said lug on the drill head, adjacentsaid socket and tend to resist the removal of said spring when saiddrill bit is forcefully removed.

'7. The combination with a drill head having a plurality of curvedsockets, of a curved drill bit for each socket and a normally straightbinding spring with an integral shouldered terminal; said bit adapted torest in flanking relation with said spring and against said shoulderedterminal thereof and the two together adapted to be forcefully insertedinto one of said sockets, thus curving the normally straight bindingspring and forcing the consequent flanking pressure thereof against theflanking side of the bit, holding the bit in place.

8. The combination in a drill comprising a drill head having a pluralityof bit sockets curved throughout their length, a drill bit for eachsocket shaped in the form of the sockets, a metallic binding springnormally straight and having integral stop means at its inner end fordefining the depth of insert for the drill bit when the bit restsagainst the same, as it flanks the sides of the spring; whereby whensaid spring and bit are together forcefully inserted into one of saidcurved sockets of the drill head then the tendency of said normallystraight springy binding member to resume its straight position as it isforcefully inserted into the curved socket, will cause a flankingpressure to be exerted against the contacting sides of the sockets anddrill bit tending to hold the bit into operative position in the socket,and means provided integral with said binding spring for resistingremoval thereof from said socket when the drill bit is forcefullyremoved.

MILTON J. KI'I'I'RELL.

